Jewelry Casting Weight: Estimating Metal from a Wax or Resin Pattern
Before casting, you need to know how much metal to melt. The standard shortcut compares the density of the pattern material with the density of the metal.
Published by the Heartline Works team · Last reviewed 2026-10-02 · Editorial policy
The density-ratio method
Metal weight ≈ pattern weight × (metal density ÷ pattern density). The ratio works because both objects have the same volume.
| Metal (typical) | Density g/cm³ | Ratio to 0.95 wax |
|---|---|---|
| Silver 925 | 10.36 | 10.9× |
| Gold 14K | 13.0 | 13.7× |
| Gold 18K | 15.5 | 16.3× |
| Platinum | 21.45 | 22.6× |
Alloy densities vary with composition, so treat these as typical values and ask your metal supplier for the figure for your alloy.
Add an allowance
Casters add metal for the sprue, button and reservoir, and for losses. The allowance depends on the setup and your own experience; the calculator lets you enter a percentage.
Volume from CAD
If you have a 3D model, the volume in mm³ ÷ 1000 gives cm³; multiplying by density gives grams.
Try the tools
- Casting Weight Calculator — Estimate finished metal weight from model volume or from a wax/resin pattern weight.
- Metal Density Calculator — Weight, volume or density from the other two, with a reference density list.